The invention relates to a method and apparatus for controlling lighting fixtures and, more particularly, to a method and apparatus for alerting occupants in a lighted area that the timing cycle of the lighting fixtures is due to expire.
Many recreational facilities require a significant number of lighting fixtures for adequate illumination and, therefore, use a significant amount of power to operate the fixtures. To reduce power consumed to light these facilities, a number of facilities use lighting control systems which control when the lighting fixtures are energized. For example, a step-dimming system, such as the two-level lighting control system disclosed in U.S. Pat. No. 5,216,333 to Nuckolls, can be used to switch facility fixtures between energy saving, low-level or reduced wattage operation, and full-level or normal wattage operation in accordance with output signals from a motion sensor. Step-dimming systems can respond to other conditions besides occupancy levels such as ambient light level, time and manual switching. U.S. Pat. No. 4,713,598 to Smith discloses another device for controllably switching an AC line to energize a load. The device uses a passive infrared (PIR) detector to sense motion.
However, PIR sensors do not work well in outdoor conditions. Temperature and sun light can affect the sensing ability of these types of sensors. Additionally, timing devices can be used; however, it can be difficult to set a suitable time out (TO) period. For example, it is difficult to anticipate the amount of time period an occupant needs a facility and preprogram a corresponding time out period. This problem is particularly apparent with respect to recreational facilities because the time a user requires a recreational facility can vary depending on the users, and the game or event.
Another problem with existing lighting control devices is that the end user does not know when illumination of lighting fixtures, which are subject to time out operation, will end. For instance, if an end user reserves a facility for two hours and does not monitor the amount of time that has elapsed, the illumination of the facility may terminate unexpectedly, creating sufficient darkness in the facility to make it difficult for the end user to find the lighting control and reset the timer.
Another problem with existing lighting control devices is that they only interface with a low voltage two-wire lighting fixture. There presently is no lighting control device that interfaces with a high voltage two-wire lighting fixture.
Therefore, a lighting control system is needed to provide time out periods that can be used outdoors, as well as indoors, that is not subject to temperature or extraneous lighting conditions, that can be reset by an end user before a facility goes dark and that is easy to operate by the end user. It would also be useful to have a lighting control system that can interface with fixtures in either of an industrial or commercial power system (e.g. 480 VAC) and a residential power system (e.g., 120 VAC).
An apparatus and method for controlling a plurality of lighting fixtures are provided. The apparatus comprises a start controller for providing power to the plurality of lighting fixtures. A control power timer is connected to the start controller for providing a first time period for illumination of the plurality of lighting fixtures, wherein the start controller is operable to interrupt power to the plurality of lighting fixtures when the first time period expires. A control timer is connected to the control power timer for providing a second time period for illumination of the plurality of lighting fixtures, wherein the second time period commences and then elapses before the end of the first time period. A control flasher is connected to the control timer for alternating the plurality of lighting fixtures between a high power state and a low power state during the second time period for illumination. An end user is alerted to the termination of the illumination of the plurality of lighting fixtures before termination occurs.